US20140373837A1 - Inhalation device for powdered drugs - Google Patents

Abstract

The invention refers to an inhalation device for powdered drugs to be received by a patient by an inhalation-caused air stream, comprising at least one powder reservoir, metering means for repeatedly metering a powder dose from the reservoir, a transportation mechanism for moving said metering means from a filling position for receiving a powder dose into an emptying position for releasing said powder dose into a powder channel, at least one activating device for manual operation by the patient being operatively connected to said transportation mechanism such that upon operation a single powder dose is being metered, said activating device comprising a dosage key (5) acting on said transportation mechanism when actuated by the patient. According to the invention, said transportation mechanism furthermore comprises a dosage lever (6) acting on said metering means, said dosage lever (6) being locked in the inhalation position of said metering means after said dosage key (5) has been properly pressed down by the patient. The dosage lever (6) in the inhalation position engages a trigger member and is releasable by actuation of the trigger member. The trigger member comprises at least one cam surface and the dosage lever (6) engages the cam surface tangentially in said locked inhalation position.

Description

• The invention refers to an inhalation device for powdered drugs to be received by a patient by an inhalation-caused air stream, comprising at least one powder reservoir, metering means for repeatedly metering a powder dose from the reservoir, a transportation mechanism for moving said metering means from a filling position for receiving a powder dose into an emptying position for releasing said powder dose into a powder channel, and at least one activating device for manual operation by the patient, said activating device being operatively connected to said transportation mechanism such that upon operation a single powder dose is being metered, said activating device comprising a dosage key acting on said transportation mechanism when pressed by the patient.
• A powder inhaler of above-referred kind is for instance disclosed inEP 1 616 592 B9.
• In the field of treating bronchial diseases but also other diseases in which medication can be affected by way of the respiratory tract, it is generally known to apply medicaments in powder form. Of course, in the art are also known devices for atomization of solutions of suspensions to provide inhalable aerosols.
• The present invention relates to an inhaler for the administration of powdered pharmaceuticals in form of a multi-dose dry powder inhaler, preferably with a dosing counting or indexing means provided in the inhaler or on a cartridge for powdered pharmaceuticals.
• As aforementioned, an inhaler of this kind is disclosed inEP 1 616 592 B9. This reference refers to an inhaler for providing a large number of doses of a pharmaceutical powder medicament from a single reservoir space which medicament can be received by the patient by means of an air stream which has to be induced by suction to a mouthpiece by the patient.
• For multi-dose inhalers an important design aspect is the metering accuracy of the device.
• Another important design aspect of inhalation devices of the above-referred kind are the use properties of the device.
• The inhalation device has to be designed such that the user clearly may make out whether the device is ready for inhalation, and whether the device has a certain and sufficient residual amount of powder doses. Moreover, the device has to be sufficient fail-safe and safe against operating errors of the user. For instance double dosing has to be prevented in any event by an appropriate design of the metering technique.
• In particular,EP 1 616 592 B9 refers to a locking mechanism, locking an activation device and/or transportation mechanism of the inhaler after a pre-determined number of metering cycles.
• This known inhalation device comprises an activating device for manual engagement by the patient for repeatedly metering a dose of medicament to be administered to the patient, an advancing mechanism for advancing a counting or indexing means each time the activating device has been engaged by the patient so that a dose of medicament has been released for administration to the patient, the counting or indexing means comprises an index, the index being detectable by a detection means of the inhaler, and the detection means being coupled to a locking mechanism, the locking mechanism blocking the activation device and/or any transportation mechanism of the inhaler delayed by a pre-determined number of metering cycles since detection of the index. The activating device is arrested in a position different from the operating position indicating the blocking state of the inhaler. This arrangement allows to block further use of the inhaler after removal of a number of doses from the reservoir space or an approximate number of doses left in the reservoir space with a simple, inexpensive and reliable mechanism so that an improved security of the patient using the inhaler can be obtained. In this manner, a patient is prevented from trying to dose from an empty reservoir space causing an inappropriate lack of required medicine. Insofar, the known inhalation device provides an enhanced usability.
• WO 2008/077623 A1 discloses an inhalation device for powder drugs comprising at least one storage chamber for accommodating a plurality of drug powder doses and a dosing device which includes at least one dosing slider which is moveable with a translatory movement in a dosing slider passage from a filling position into an emptying position, wherein the inhalation device further includes a device for inhalation-triggered automatic movement of the dosing slider from its filing position into the emptying position and a return device for automatic movement of the dosing slider back into the filling position. The device for inhalation-triggered automatic movement of the dosing slider comprises a pivotally mounted spring-loaded flap arranged into an air passage. The spring-loaded flap cooperates with a thrust rod which releases the device for inhalation-triggered automatic movement of the dosing slider when the flap is deflected out of its rest position by an airflow through the air passage upon inhalation by the patient. This requires a predetermined minimum airflow in the air passage to be exceeded. For comprehensive moisture protection for the medicament in the storage chamber of the cartridge, the inhalation device according to WO 2008/077623 A1 includes a dosing slider passage which has a corresponding opening at its open ends to which the dosing slider can issue with the dosing cavity, wherein a contact surface or a seal is provided around the opening and wherein the dosing slider further has a sealing surface, which is arranged in a plane approximately transverse relationship with the direction of movement out of the filling position into the emptying position. The sealing function may be provided by elastic seal disposed on the contact surface of a sealing surface of the dosing slider. These sealing measures, however, do not contribute to the issue of reproducible triggering forces.
• It is generally desirable to have a defined trigger threshold for accomplishing such inhalation-triggered automatic movement of the dosing slider. It will be readily apparent for a person skilled in the art that a certain bandwidth for the required triggering forces, i.e. a certain air flow variation for the suction to be applied by the patient is unavoidable due to the tolerances of the moveable parts of such an inhaler.
• U.S. Pat. No. 6,071,498 discloses an inhalation device for powdered drugs with prevention means for double or repeated dosages. The device contains a powder reservoir, metering means for repeatedly metering a powder dose from the reservoir, a transportation mechanism from moving said metering means from a filling position for receiving a powder dose into an emptying position for releasing said powder dose into a powder channel, a dosage key, acting on said transportation mechanism when pressed by the patient, said transportation mechanism comprising a dosage lever acting on said metering means, wherein said dosage lever is locked in the inhalation position of said metering means after said dosage key has been actuated by the user. In the locked position, the dosage lever is engaged with a catch hook in a recess with a blocking edge in the shaft of a flap valve functioning as a trigger member. The engagement of the metering lever/dosage lever with its catch hook in the recess is released by moving the flap valve by means of the air stream caused by inhalation with little delay, so that the metering lever is pulled back into its initial position under the load of springs. The position of the catch hook within the recess generally determines the position of the contact point of the catch hook relative to the blocking edge of the recess. Depending on the mounting tolerances of the metering lever and the flap valve as the moving parts of the inhaler, the contact point between the catch hook and the blocking edge within the recess may have a different position which actually results in more or less delay between inhalation by the user and release of the flap valve. A contact point between the catch hook of the metering lever within the recess may be very close to the blocking edge with the result that release of the flap valve occurs almost instantaneously after the flap valve starts a pivoting movement. On the other hand, the contact point between the catch hook and the metering lever within the recess may be relatively far away from the blocking edge in the shaft so that upon pivoting movement of the flap valve, there is a certain delay until the metering lever is ultimately released. In effect, this requires higher triggering forces as in the first case.
• However, it is desirable to keep the triggering forces for inhalation-triggered automatic metering as reproducible as possible. Such defined trigger threshold ultimately results in a more constant volumetric flow during inhalation so that for instance if the powder medicament to be received is in the form of an adhesive mixture, the dry powder will be more effectively deagglomerated for releasing the drug particles from the powder formulation. In effect, the dosing accuracy increases.
• It is therefore an object of the present invention to provide an inhalation device in which at least a part of the metering cycle is inhalation-triggered and in which the bandwidth for the required triggering forces is as small as possible.
• Moreover, it is an object of the present invention to provide an inhaler of the above-referred kind which is further enhanced with regard to usability and in view of eventual mal operation. This and other objects are achieved by an inhalation device according toclaims1 and10. Advantageous embodiments of the invention may be derived from the dependent claims.
• According to one aspect of the present invention, there is provided an inhalation device for powdered drugs to be received by a patient by an inhalation-induced airflow, comprising at least one powder reservoir, metering means for repeatedly metering a powder dose from the reservoir, a transportation mechanism for moving said metering means from a filling position for receiving a powder dose into an emptying position for releasing said powder into a powder channel, at least one activating device for manual operation by the patient, being operatively connected to said transportation mechanism such that upon operation a single powder dose is being metered, said activating device comprising a dosage key acting on said transportation mechanism, wherein said transportation mechanism comprises a dosage lever acting on said metering means, said dosage lever locked in the inhalation position of said metering means after said dosage key has been properly actuated and wherein said dosage lever in the inhalation position engages a trigger member and being releasable by actuation of the trigger member, wherein the trigger member comprises at least one cam surface and wherein the dosage lever engages said cam surface tangentially in said locked inhalation position.
• With the inhalation device according to the invention, the metering cycle will only be completed and the transportation and/or metering means will only be reset after inhalation of a metered quantity of powder by the patient. Inhalation will cause the trigger member to release said dosage lever which will reset the metering means into its filling/receiving position. Since the dosage lever only engages said cam surface of the trigger member tangentially, the contact force between the dosage lever and the trigger member is almost independent from the tolerance of the components.
• In other words, the trigger member comprises a cam surface which forms a curve which is engaged or contacted by the dosage lever peripherally from outside such that the fastening hook makes line contact with the cam surface. The position of the contact point/contact line between cam surface and the dosage lever is almost the same, i.e. remains stable, irrespective of the angular end position (locked position) of the trigger member relative to the dosage lever.
• According to one advantageous aspect of the invention, the trigger member comprises an inhalation-operated valve in an air duct communicating with said powder channel. The inhalation-operated valve is operatively connected to said dosage lever so that the dosage lever is releasable by action of the valve initiated by the suction generated by the patient during inhalation. The inhalation-operated valve may be for instance in the form of a spring-loaded flap which due to the resilience of the spring is normally held in closed position.
• The dosage lever may comprise a fastening hook engaging behind and/or under said cam surface in the inhalation position.
• In one advantageous embodiment of the inhalation device according to the invention, the fastening hook comprises a planar contact surface making line contact with the cam surface in the inhalation position. Due to the fact that the fastening hook only tangentially engages the cam surface, excursion of the contact surface due to the tolerances of the parts of the inhaler is only possible in axial direction, which, however, has no impact on the required triggering forces.
• Triggering of the dosage lever is achieved by a pivot motion of the cam surface so that only a slight pivoting movement of the triggering member almost instantaneously releases the dosage lever. Due to this design, the bandwidth of required air flow variation for the suction to be applied by the patient can be kept remarkably below 30 l/min.
• In one advantageous embodiment, the inhalation-operated valve may include a flap which fulfils a pivot movement upon inhalation, said cam surface being provided on the flap or on a pivot shaft of the flap. The flap is for example a major component of the aforementioned valve. The pivot axis may extend in the centre of gravity of the flap or nearby the centre of gravity of the flap. In the event the cam surface is also arranged nearby the pivot axis or nearby the centre of gravity of the flap, easy triggering may be achieved.
• According to yet another aspect of the present invention, there is provided an inhalation device for powder drugs to be received by a patient by an inhalation-caused air stream/inhalation-caused air flow, comprising at least one powder reservoir, metering means for repeatedly metering a powder dose from the reservoir, a transportation mechanism for moving said metering means from a filling position for receiving a powder dose into an emptying position for releasing said powder dose into a powder channel, at least one activating device for manual operation by the patient, said activating device being operatively connected to said transportation mechanism such that upon operation a single powder dose is being metered, said activating device comprising a dosage key acting on said transportation mechanism when pressed by the patient, and at least one powder disintegration means, wherein said metering means and said transportation means are arranged within a dosing compartment and said disintegration means is arranged in a powder discharge compartment, and wherein said dosing compartment is sealed against said powder discharge compartment.
• A powder disintegration means in the sense of the instant application is a means for breaking up a powder agglomerate or releasing drug particles from a carrier material. Said powder disintegration means may include means for guiding powder and air as well as a cyclone/air classifier.
• Sealing the dosing compartment of the inhaler relative to said powder discharge compartment also remarkably reduces the variation in required air flow for triggering. Accordingly, this design avoids the possibility of sucking an airflow through the inhaler which by-passes the powder channel and/or an air duct of the device.
• In one advantageous embodiment, the inhalation device according to the invention further comprises a main structural support member defining a valve chamber as well as support for a housing including at least two shells.
• In a preferred embodiment, the valve chamber is sealed against the housing so as to define said dosing compartment and said powder discharge compartment.
• A seal may be provided in the form of a resilient lip extending completely around the valve chamber in an uninterrupted fashion.
• Alternatively, the sealing between the dosing compartment and the powder discharge compartment may be provided in form of a labyrinth seal. The valve chamber may comprise a rigid sealing rib extending completely around the valve chamber and engaging corresponding sealing grooves within the shells of the housing so as to form a labyrinth.
• In the following the invention is disclosed by way of example with reference to accompanying drawings in which:
• FIG. 1 shows a perspective view of an embodiment of an inhalation device according to the invention with the mouthpiece cap opened,
• FIG. 2 shows an exploded view of the inhaler according to the invention,
• FIG. 3 shows a partial longitudinal cross-sectional view through an inhaler according to a first embodiment of the invention,
• FIG. 4 shows another longitudinal cross-sectional cut through the inhaler according to the first embodiment of the invention,
• FIG. 5 shows a perspective view of a dosage key according to the invention,
• FIG. 6 shows a cross-sectional view of the inhaler in a non-actuated state of the dosage key,
• FIGS. 7a,7bshow a cross-sectional view corresponding to the view shown inFIG. 6 where the dosage key is partially pressed,
• FIG. 8ashows a cross-sectional view according toFIGS. 6 and 7 where the dosage key is fully depressed,
• FIG. 8bshows a perspective view demonstrating the engagement of the dosage lever into the flap valve,
• FIG. 9 shows a perspective view of a dosage lever of the inhaler according to the present invention,
• FIG. 10 shows a perspective view of a first preferred embodiment of an inhalation-operated valve closing the air duct of the inhaler according to the invention,
• FIG. 11ashows another perspective view of the inhalation-operated valve according toFIG. 10,
• FIG. 11bshows a perspective rear view of an inhalation-operated valve according to a second preferred embodiment,
• FIG. 12 shows a perspective side view of the inhaler according to the invention without its housing,
• FIG. 13 shows an enlarged detail ofFIG. 12 as a rear view,
• FIG. 14ashows an enlarged detail of the engagement between the dosage lever and an inhalation-operable flap valve of the inhaler according to a first preferred embodiment of the invention,
• FIG. 14bshows an enlarged detail of the engagement between the dosage lever and the flap valve according to the first preferred embodiment,
• FIG. 14cshows an enlarged detail of the engagement between the dosage lever and the flap valve according to a second preferred embodiment,
• FIG. 15 shows another longitudinal sectional view through the inhaler,
• FIG. 16 shows a perspective view of a powder cartridge of the inhaler according to the invention,
• FIG. 17 shows a perspective view of the inhaler housing,
• FIG. 18 shows a detail of the counter slide gliding over the counter ring's tooth,
• FIG. 19 shows a detail of the cartridge's locking ratchet (locking lever not displayed),
• FIG. 20 shows a detail of the locking lever and its engagement with the dosage key and the counter ring.
• Theinhaler1 shown inFIGS. 1 to 20 is an inhaler for powdered medicaments, for providing a large number of doses of a pharmaceutical powder medicament from a receptacle in the form of a powder cartridge. Thepowder cartridge3 defines areservoir2 for receiving a large number of doses of a pharmaceutical powder/powdered drug. In the described embodiment, the typical number of doses which may be obtained from onepowder cartridge3 may be in the range of 30 to 60 doses.
• Thereservoir2 is sealingly covered by alid4 as can be seen fromFIG. 2. The lid is secured to thecartridge body3ain the assembled state of the inhaler in a non-removeable fashion.
• The powder medicament can be received by a patient by means of an air stream caused by the user, i.e. induced by suction. Therefore, the inhaler further comprises an activating device for manual engagement by the patient in the form of adosage key5 being connected to a transportation mechanism including adosage lever6 and a lockinglever7. Thedosage lever6 acts on adosage slide8 as a metering means being moveable from a filling position for receiving a powder dose into an emptying position for releasing said powder dose into apowder groove16aof acyclone16 for deagglomeration of the powder in thecyclone16. From thepowder groove16athe patient can inhale the powdered drug through amouthpiece10 via an air stream generated by the patient. If not in use, themouthpiece10 is protected from dirt by amouthpiece cover11. Themouthpiece cover11 is secured to the inhaler housing fixedly, i.e. non-detachable.
• Thepowder groove16aof thecyclone16 forms a part of a powder channel through thecyclone16 which functions as a disintegration means as this is known from the art. The powder medicament to be received by the patient may be in form of an adhesive mixture. Adhesive mixtures consist of relatively large crystals, generally α-lactose-monohydrid, carrying the micronised drug particles on their surface. In the disintegration system, the dry powder will be deagglomerated for releasing the drug particles from the powder formulation. Thecyclone16, i.e. the disintegration means, generally includes an air circulation chamber as well as several air supply channels which enter the circulation chamber tangentially so that a circular air flow pattern is created inside the circulation chamber. So the total respiratory flow through the inhaler does include a transportation airflow for traversing the powder dose in the powder groove and dragging the powder into the circulation chamber, a cyclone air flow which tangentially enters the circulation chamber as well as eventually a bypass airflow for creating a so-called sheath flow of clean air. A possible design for the disintegration means is for instance disclosed in the international patent publication WO 03/000325 the disclosure of which is herewith fully incorporated by reference. The disintegration means in the following in a rather simplified form is referred to as a cyclone. In a also rather simplified form in the following the air path from thepowder groove16ato the mouthpiece opening is referred to as powder channel. It is, however, to be understood that the term “powder channel” does not necessarily refer to one distinct single powder channel but rather to a channel system as explained above.
• As this can be taken fromFIG. 2, theinhaler1 includes a three-parthousing comprising shells12 and13 as well ascover14 received on theshells12 and13 via snap-fit connection in a non-releasable fashion.
• The heart of theinhaler1 is formed by avalve chamber15 including thecyclone16 and acartridge body3a.
• Manual operation of theinhaler1 by a patient functions viadosage key5 which on depression by the patient against the biasing force of a dosagekey spring17 acts on adosage lever6 which is connected to the dosage slide8 (seeFIG. 15).
• Dosage slide8 is slidably moveable withindosage slide passage18 extending below thereservoir2 within thecartridge body3a, as this for instance can be seen fromFIG. 15.
• The dosage slide8 (metering means) includes adosage cavity19 for receiving a metered dose of a powdered drug.
• It should be mentioned that thecartridge body3anot only defines thereservoir2 for receiving the powdered drug but also defines adosage slide passage18 extending below thereservoir2 as well as a housing for receiving counting and indexing means as this is described hereinafter more detailed.
• Thedosage slide8 is shown inFIG. 15 in its emptying position where thedosage cavity19 is aligned with anopening20 in thevalve chamber15 communicating with thepowder groove16aof thecyclone16. Thedosage slide8 is moveable viadosage lever6 between a filling position where thedosage cavity19 is aligned with anopening21 of thereservoir2 within thecartridge body3aand an inhalation/emptying position. In the filling position, thedosage cavity19 receives a metered quantity of powder. Upon actuation of thedosage key5, thedosage slide8 will be advanced into the position shown inFIG. 15, thereby releasing the powder dose into thepowder groove16athrough theopening20.
• In this position shown inFIG. 15, the inhaler is ready for inhalation. In the event the patient applies suction viamouthpiece10, this forces aflap valve22 at the very end of anair duct9 to swing open so that an air flow can freely circulate from the open end of theair duct9 into a powder channel defined by thevalve chamber15 and thepowder groove16aof the cyclone, into the mouthpiece. Theflap valve22 includes theflap22aand ashaft22bwhich are in the disclosed embodiment integrally formed.
• Theflap valve22 according to a first embodiment in more detail is shown inFIGS. 10 and 11a. Theshaft22bof theflap valve22 at its ends is pivot mounted withinvalve chamber15.
• As this can be seen also fromFIG. 15, in the inhalation position theflap valve22 is engaged by afastening hook23 of thedosage lever6.
• A rear side view of theflap valve22 is for instance shown inFIG. 10. Theflap22 has an angled/bent profile including threelegs22c,22dand22e, thefirst leg22cin the mounting position being inclined towards the closing direction of theflap valve22, thesecond leg22dbeing inclined rearwardly and thethird leg22eextending in forward direction and approximately tangentially to the rotary movement of theflap valve22.
• On the rear side of thefirst leg22cof theflap22a, a latchingrib47 is provided which may be engaged by thefastening hook23 of thedosage lever6 in the inhalation position. Thefastening hook23 of thedosage lever6 at its leading end is provided with abarbed projection50 which has a slopingface51. Theflap valve22 includes aflap valve lever31 integrally formed with saidshaft22b. The distal end of theflap valve lever31 is provided with adeflector surface53. Upon actuation of thedosage key5 and subsequent actuation and downward movement of thedosage lever6, a correspondingdeflector surface53′ of alatch29 integrally formed with thehook23 of thedosage lever6 gets into abutment with thedeflector surface53 of theflap valve lever31. Theflap valve lever31 as well as the hook of the dosage lever are thereby both being slightly deflected, i.e. bent aside and snap back in their initial position upon further downward movement of thehook23 of thedosage lever6. Upon further downward movement of thehook23, the slopingface51 of thebarbed projection50 abuts one edge of the latchingrib47. Thereby thehook23 is bent aside due to the resilience of its material and snaps back behind the latchingrib47 in its end position thereby engaging theflap valve22 and being releasable by an inhalation-triggered pivoting movement of theflap valve22.
• As this can particularly seen fromFIG. 14b, which shows an enlarged longitudinal cut through theflap22a, thebarbed projection50 of thehook23 engages the latchingrib47. When theinhaler1 is ready for inhalation, the latchingrib47 includes acurved bearing surface54 facing thebarbed projection50. The bearingsurface54 which defines a cam surface almost providing line contact between thebarbed projection50 of thehook23 and the latchingrib47 so that the contact force between the latchingrib47 and thehook23 is almost independent from the tolerances of the components. To be more specific, the planar surface of thebarbed projection50 of the hook engages thecurved bearing surface54 only tangentially so that in effect excursion of the contact surface due to tolerances of the parts of the inhaler is only possible in axial direction, which, however, has no impact on the required triggering forces. Due to this design the required triggering forces are only subject to minor variations so that triggering of theflap valve22 is fairly reproducible. It is readily apparent fromFIG. 15 that if theflap22amoves in clockwise direction, thehook23 is released almost instantaneously. As a result, the dosage lever may swing upwards driven by the force of thedosage lever spring25. This upward movement will cause thedosage slide8 to return to its powder receiving position.
• Another embodiment of theflap valve22 is shown inFIGS. 11band14c. Same parts of theflap valve22 are denoted by the same reference numerals.
• Theflap valve22 according to this embodiment comprises a relatively simpleflat flap22awhich is not bent or angled in itself.
• As this can be taken fromFIG. 14c, thefastening hook23 engages theshaft22bof theflap valve22 when theinhaler1 is ready for inhalation.
• Theshaft22bof the flap valve22 (see for instanceFIG. 11b) has a cut outarea24 which is arranged approximately in the middle of theshaft22bsuch that, if theflap22aswings open (inFIGS. 14cand11bin clockwise direction), thefastening hook23 of thedosage lever6 tangentially engaging theshaft22bapproximately in the middle of theshaft22b, will be released so that thedosage lever6 driven by the force of thedosage lever spring25 may return to its initial position, thereby moving thedosage slide8 back into the filling position for receiving a powdered dose from the reservoir/powder cartridge. Upon actuation of thedosage key5 thedosage lever6 will be moved downward while partially pivoting theflap22aby contact of thelatch29 of thedosage lever6 with theflap valve lever31. After partially pivoting theflap valve22 swivels back to its starting position by the force of its molded, integrally formedspring32. The pivot motion of theflap22acaused by the contact of thelatch29 with theflap valve lever31 allows thelatch29 to engage behind themechanical stop30 of theflap valve lever31 upon early release and upward movement of thefastening hook23.
• In the area of the cut outportion24 of theshaft22b, theshaft22bhas only a semi-circle cross-section, the leading end of thefastening hook23 engages the remainder of the cross-section of the shaft only tangentially and only in a very limited surface area (line contact) so that the contact force between theshaft22band thefastening hook23 is almost independent from the tolerances of the components. Due to this design, in particular due to the fact that a planar contact surface of thefastening hook23 contacts a curved surface area of the remainder of the cross section of theshaft22b, the required triggering forces are only subject to minor variations so that triggering of theflap valve22 is fairly reproducible. Only a slight rotation/pivoting movement of theshaft22band theflap22awill set thefastening hook23 free so that thedosage lever6 may swing upwards driven by the force of thedosage lever spring25, thereby finishing the inhalation cycle.
• A perspective view of thedosage key5 is shown inFIG. 5. Thedosage key5 is held in its initial position/starting position by dosagekey spring17 which abuts atongue member26 integrally formed with thedosage key5.
• Saiddosage key5 includes anactuator blade27 being formed as a flexible arm/leg also integrally formed with thedosage key5 and extending downwards in the mounting position shown inFIG. 5. As this can be seen from the operating sequence shown inFIGS. 6 to 8a,valve chamber15 is provided with abeveled edge28 forming a kind of cam surface for theactuator blade27 upon depression of thedosage key5.
• FIG. 6 shows a cross-sectional cut through theinhaler1 where thedosage key5 is in its not-operated starting position. Theactuator blade27 in this state is not engaged with the transportation mechanism, i.e. with thedosage lever6.
• Upon depression of thedosage key5, theactuator blade27 moves downwards and engages thebeveled edge28 of the valve chamber such that theactuator blade27 due its inherent flexibility is deflected/bent from a first position shown inFIG. 6 to a second position inFIG. 7awhere it engages at the same time thedosage lever6. By a further movement of thedosage key5 and theactuator blade27, theactuator blade27 urges thedosage lever6 downwards against the biasing force ofdosage lever spring25. Upon full depression of thedosage key5, which is shown inFIG. 8a,actuator blade27 snaps back in its non-deflected and disengaged position. In this position thefastening hook23 of thedosage lever6 engages the latchingrib47 of theflap valve22 as this is also shown inFIG. 8a. The device/inhaler is now ready for inhalation.
• In the following the double dosing prevention mechanism of the inhaler according to the invention will be described, first referring to the first embodiment of theflap valve22 according to the invention.
• As this has been mentioned before, thedosage lever6 in the area of its trailing end (left hand side inFIG. 9) is provided withlatch29. Upon downward movement of the dosage lever as a result of the actuation of thedosage key5, first of all thecomplementary deflection surface53′ of thelatch29 gets into abutment with thedeflector surface53 of theflap valve lever31. As a result, theflap valve lever31 is bent aside/deflected while being passed by thefastening hook23 and snaps back into its initial position upon further downward movement of thedosage lever6, which ultimately will result in engagement of the hook and the latchingrib47.
• It is again referred toFIG. 9 which shows a perspective view of thedosage lever6. In the area of its trailing end (left hand side inFIG. 9), thedosage lever6 is provided with alatch29 for engaging amechanical stop30 of aflap valve lever31 integrally formed with saidshaft22bon a return movement of thedosage lever6.
• In the event thedosage key5 will be pressed and released too early, i.e. prior to the engagement of thefastening hook23 into the latchingrib47 of theflap valve22, latch29 of thedosage lever6 upon upward movement of thedosage lever6 will abut saidmechanical stop30 of theflap valve lever31. Accordingly, thedosage lever6 locks into theflap valve22 in a middle position. This middle position lock provides a double dosing prevention mechanism. In this middle position lock, i.e. first locked position, the relationship of lever is such that the forces required for releasing thedosage lever6 can not be brought up simply by inhalation. If thedosage lever6 does not lock intoflap valve22 in the end position, e.g. when thedosage key5 is not pressed all the way down, thedosage lever6 will not return to its initial starting position, i.e. will be locked in the middle position. Accordingly, no additional powder dose will be released from thereservoir2. Thedosage lever6 and thedosage slide8 will only return into their starting position after inhalation-triggered actuation of theflap valve22, thereby releasing thefastening hook23 of thedosage lever6.
• A double-dosing prevention mechanism is also provided with the design of theflap valve22 of the second embodiment according toFIG. 14c. Upon actuation of thedosage key5, thedosage lever6 will be moved downward while partly pivoting theflap22aby contact of thelatch29 of the dosage lever with theflap valve lever31. After partly pivoting the flap upon downward movement of the dosage lever, theflap valve22 will return into its closed position due to the resilience of aspring32 integrally molded with theflap valve22.Latch29 of thedosage lever6 upon an early upward movement of thedosage lever6 will abut themechanical stop30 of theflap valve lever31. Accordingly, thedosage lever6 locks into theflap valve22 in a middle position.
• Dosage lever6 includes a cam-like actuating element33 which upon each actuation moves acounter slide34 of the cartridge so that acounter ring35 of the cartridge is moved by one count towards a lower dose. The degree of the cartridge's content is accordingly visible in adisplay window36 of thecartridge body3aindexing the fill status of the cartridge. Details of thecounter slide34 acting on thecounter ring35 may be taken fromFIG. 18.Counter ring35 which is designed as a ratchet ring withteeth37 is rotably inserted into a collar of thecartridge body3a. Upon actuation of thedosage lever6, theactuating element33 moves thecounter slide34, the counter slide engaging the counter ring'steeth37, thereby moving thecounter ring35 so that the next index number is indicated in thedisplay window36. Thecounter ring35 for instance provides a visual indication of a dose count for each 5^thdosing step/metering cycle. The counter ring for instance shows thirteen numbers and indicates a countdown from 60 to 0 upon each metering cycle. Each tooth of thecounter ring35 represents one metering cycle.
• As this also can be taken fromFIG. 4, thecounter slide34 includes apawl43 integrally formed with thecounter slide34. Thepawl43 is biased towards thecounter ring35 that it firmly engages theteeth37 of thecounter ring35. Theteeth37 are unsymmetrical insofar as they have one sloping flank and one vertically extending flank, the sloping flank representing the leading flank with respect to the rotational direction of thecounter ring35.
• Thecounter slide34 is moveable back and forth within a slidingchannel44 of thecartridge body3a. The cam-like actuating element33 of thedosage lever6 extends into the slidingchannel44 and into arecess45 of the horizontally extending part of thecounter slide34. Engagement of theactuating element33 with thecounter slide34 transforms a pivoting movement of theactuating element33 into a linear movement of thecounter slide34.
• Upon depression of thedosage key5, the dosage lever will be pivoted such that theactuating element33 is pivoted towards the left hand side inFIG. 4. At the same time, the lower leadingend46 of the dosage lever (seeFIGS. 9 and 12) pushes thedosage slide8 into its emptying/inhalation position. Thecounter slide34 is thereby moved in the opposite direction. While thecounter slide34 fulfills this movement, thepawl43 engages the vertical flank of therespective tooth37 of the counter ring, moving the counter ring one count/step. After release of thedosage lever6, thecounter slide34 will be moved backwards into its starting position. Due to the resilience of thepawl43, the pawl may glide over the sloping flank of the respective tooth, thereby snapping back behind the tooth. As this can be seen fromFIG. 19, the counter mechanism includes a lockingratchet38 engaging thecounter ring teeth37. Due to the geometry of theteeth37, the lockingratchet38, which is also a resilient member, blocks an anti-clockwise rotation of thecounter ring35.
• As this can be seen fromFIG. 12, theinhaler1 includes a lockinglever7 which is pivotably mounted in thevalve chamber15 betweendosage key5 anddosage lever6. The lockinglever7 includes a blockingarm39 and aspring leg40. During assembly of thepowder cartridge3, the lockinglever7 is pushed downwards, the blockingarm39 and thespring leg40 thereby being moved backwards. In this position, thedosage key5 may be freely moved downwards against the biasing force of thespring leg40 as shown inFIG. 12.
• Thedosage key5 is also freely moveable against the biasing force of the dosagekey spring17 as shown inFIG. 15.
• Thecounter ring35 includes anotch41 being engageable by atongue42 of the lockinglever7.
• The notch is arranged on thecounter ring35 such that, after a pre-determined number of doses has been delivered, the lockinglever7 engages the notch in the counter ring with a pivoting movement caused by the action ofspring leg40 actuated by thedosage key5. Upon upward movement of the lockinglever7, the blockingarm39 of the lockinglever7 is pushed forward (towards the mouthpiece10) and engages thedosage key5 in its lowest position such that thedosage key5 stays blocked in its lowest position after the last inhalation. It is impossible to perform another activation of the empty device.
• As this can be seen fromFIGS. 5 and 20, thedosage key5 includes anactuation rib55 acting on thespring leg40 only while being in depressed condition in order to avoid fatigue of thespring leg40. Thespring leg40 is accordingly only biased if thedosage key5 is being pressed or held downward.
• Apart from the indexing means in the form of the counter ring, the device includes anotherinhalation control window48 indexing whether the device is ready for inhalation or not. The inhalation control window shows for instance a green-colored flag in the event the device is ready for inhalation. This is because in the activated status of the inhaler1agreencolored tab49 of thedosage lever6 covers a red colored flag in theinhalation control window48. The reset of the device from the inhalation position into the starting position takes place during inhalation by means of an airflow upon inhalation.Flap valve22 is deflected thus releasing thedosage lever6 as this has been described in detail before.
• In order to ensure leak tightness of theair duct9, theshells12 and13 may be sealed againstvalve chamber15 by means of one or more sealing ribs which extend aroundvalve chamber15. The sealing rib may be in form of a thermoplastic elastomer which has been co-injection molded withvalve chamber15. Alternatively, the sealingrib52 may be designed as a resilient ring which has been mounted into a sealing groove during assembly of the inhaler.
• In a particularly preferred embodiment of the inhaler according to the invention, theshells12 and13 are sealed against the valve chamber by a labyrinth seal which completely extends around thevalve chamber15, so that thevalve chamber15 including thecyclone16 and thepowder groove16ais effectively sealed against the dosing compartment of the inhaler. The labyrinth seal is provided by a sealingrib52 completely extended around thevalve chamber15 and in the assembled state of theinhaler1 engaging a corresponding sealing groove in theshells12 and13. This sealing assists in keeping the triggering forces for theflap valve22 as reproducible as possible. The bandwidth for the required triggering forces normally corresponds to an air flow variation of 30 l/min for the suction to be applied by the patient. Sealing the valve chamber of theinhaler1 against theshells12,13 remarkably reduces this variation in required air flow for triggering theflap valve22. Accordingly, this design avoids the possibility of sucking an air flow through the inhaler which bypasses the powder channel and/or theair duct9.
REFERENCE NUMERALS
• 1 inhaler
• 2 reservoir
• 3 cartridge
• 3acartridge body
• 4 lid
• 5 dosage key
• 6 dosage lever
• 7 locking lever
• 8 dosage slide
• 9 air duct
• 10 mouthpiece
• 11 mouthpiece cap
• 12,13 shells
• 14 cover
• 15 valve chamber
• 16 cyclone
• 16apowder groove
• 17 dosage key spring
• 18 dosage slide passage
• 19 dosage cavity
• 20 opening
• 21 opening
• 22 flap valve
• 22aflap
• 22bshaft of flap valve
• 22cfirst leg of flap valve
• 22dsecond leg of flap valve
• 22ethird leg of flap valve
• 23 fastening hook
• 24 cut-out portion
• 25 dosage lever spring
• 26 tongue member
• 27 actuator blade
• 28 beveled edge
• 29 latch
• 30 mechanical stop
• 31 flap valve lever
• 32 spring of flap valve
• 33 actuating element
• 34 counter slide
• 35 counter ring
• 36 display window
• 37 teeth
• 38 locking ratchet
• 39 blocking arm
• 40 spring leg
• 41 notch
• 42 tongue
• 43 pawl
• 44 sliding channel
• 45 recess
• 46 leading end of dosage lever
• 47 latching rib
• 48 inhalation control window
• 49 tab
• 50 barbed projection
• 51 sloping face
• 52 sealing rib
• 53 deflector surface
• 53′ deflector surface
• 54 bearing surface
• 55 actuation rib

Claims (12)

1. Inhalation device for powdered drugs to be received by a patient by an inhalation-caused air stream, comprising at least one powder reservoir, metering means for repeatedly metering a powder dose from the reservoir, a transportation mechanism for moving said metering means from a filling position for receiving a powder dose into an emptying position for releasing said powder dose into a powder channel, at least one activating device for manual operation by the patient, said activating device being operatively connected to said transportation mechanism such that upon operation a single powder dose is being metered, said activating device comprising a dosage key acting on said transportation mechanism when pressed by the patient, said transportation mechanism comprising a dosage lever acting on said metering means, wherein said dosage lever is locked in the inhalation position of said metering means after said dosage key has been actuated by the user, wherein said dosage lever in the inhalation position engages a trigger member and is releasable by actuation of the trigger member, wherein the trigger member comprises at least one cam surface and wherein the dosage lever engages said cam surface tangentially in said locked inhalation position.

2. Inhalation device according toclaim 1, characterized in that said trigger member comprises an inhalation-operated valve in an air duct communicating with said powder channel.

3. Inhalation device according toclaim 1, characterized in that the dosage lever comprises a fastening hook engaging behind and/or under said cam surface in the inhalation position.

4. Inhalation device according toclaim 1, characterized in that the fastening hook comprises a planar contact surface making line contact with the cam surface in the inhalation position.

5. Inhalation device according toclaim 1, characterized in that triggering of the dosage lever is achieved by a pivot motion of the cam surface.

6. Inhalation device according toclaim 1, characterized in that said inhalation-operated valve includes a flap which fulfils a pivot movement upon inhalation, said cam surface being provided on the flap or on a pivot shaft of the flap.

7. Inhalation device accordingclaim 1 further comprising at least one powder disintegration means, wherein said metering means and said transportation mechanism are arranged within a dosing compartment and said disintegration means is arranged in a powdered discharge compartment, and wherein said dosing compartment is sealed against said powder discharge compartment.

8. Inhalation device according toclaim 7 comprising a main structural support member defining a valve chamber as well as a support for a housing including at least two shells.

9. Inhalation device according toclaim 8, characterized in that the valve chamber is sealed against the housing so as to define said dosing compartment and said powder discharge compartment.

10. Inhalation device for powdered drugs to be received by a patient by an inhalation-caused air stream, comprising at least one powder reservoir, metering means for repeatedly metering a powder dose from the reservoir, a transportation mechanism for moving said metering means from a filling position for receiving a powder dose into an emptying position for releasing said powder dose into a powder channel, at least one activating device for manual operation by the patient, being operatively connected to said transportation mechanism such that upon operation a single powder dose is being metered, said activating device comprising a dosage key acting on said transportation mechanism when pressed by the patient, the inhalation device further comprising at least one powder disintegration means, wherein said metering means and said transportation mechanism are arranged within a dosing compartment and said disintegration means is arranged in a powder discharge compartment, and wherein said dosing compartment is sealed against said powder discharge compartment.

11. Inhalation device according toclaim 10, further comprising a main structural support member defining a valve chamber as well as a support for a housing including at least two shells.

12. Inhalation device according toclaim 11, characterized in that the valve chamber is sealed against the housing so as to define said dosing compartment and said powder discharge compartment.

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